(19)

(11)

EP 0 233 909 A1

(12)

(43) Date of publication: 02.09.1987 Bulletin 1987/36 (21) Application number: 86904890.0 (22) Date of filing: 18.08.1986

(51) International Patent Classification (IPC):  F16J 15/ 34( . ) (86) International application number: PCT/GB1986/000491 (87) International publication number: WO 1987/001170 (26.02.1987 Gazette 1987/05)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 20.08.1985 GB 19850020860 (71) Applicant: GEORGE ANGUS & COMPANY LIMITED Newcastle upon Tyne NE99 1TG (GB)	(72) Inventor: JOHNSTON, David, Ernest Gosforth Newcastle upon Tyne NE3 1PQ (GB) (74) Representative: Weston, Robert Dale  c/o PHILLIPS & LEIGH 7 Staple Inn High Holborn London WC1V 7QF London WC1V 7QF (GB)